Color changes of UHT milk during storage

Abstract

In this study measurements of color parameters of UHT milk were performed, by using a MOM-color 100 photoelectric tristimulus colorimeter. Colors of UHT milk samples containing 3.2% and 1.6% milk fat, processed under industrial conditions, packed in polyethylene terephtalate ( PET) based packages, and stored for 0, 15, 30, 45, 60 and 90 days at ambient temperature (20 +/- 5 degrees C) were examined. Results are shown in four different systems that define measurement of color parameters expressed in: CIE, CIE L*a*b*, Hunter and ANLAB - Adams Nickerson systems. Average value of mean reflectance of UHT milk determined in CIE system statistically is highly significantly changed, (p lt 0.01) depending on duration of storaging, percentage of milk fat, as well as on the interaction of the mentioned factors. For the UHT milk with 1.6% milk fat statistically significant (p lt 0.05) decrease of psychometric chroma b* occurs after 60 days, and for milk with 3.2% milk fat established on 45(th) day of storage.